Added function 'Normalise()' for sequences

modules/seq/base/doc/seq.rst

modules/seq/base/pymod/export_sequence.cc

modules/seq/base/src/impl/sequence_impl.cc

modules/seq/base/src/impl/sequence_impl.hh

modules/seq/base/src/sequence_handle.cc

modules/seq/base/src/sequence_handle.hh

modules/seq/base/tests/test_seq.py

modules/seq/base/tests/test_sequence.cc